Cron is a command that executes commands periodically as specified in
/etc/crontab and user-defined crontabs. In Debian 1.3 there is a
standard mechanism to execute commands in /etc/cron.daily,
/etc/cron.weekly and /etc/cron.monthly.

Cron is started from boot scripts but it seems to change it's PATH to
a pretty strange one:

/usr/bin:/binn:/sbin:/bin:/usr/sbin:/usr/bin

THIS IS LIKELY A BUG IN CRON. This is the init path where there is
/usr/bin:/bin written over the beginning without terminating 0! This
bug does not exist in all the systems.

In crontab there can be PATH definition. In Debian 1.3 there is
the following default line in the beginning of /etc/crontab:

PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin

Because of this, the PATH of crond program is never used in user
programs. All the scripts in /etc/cron.* directories get this path by
default. This path is used even if a program is executed as non-root.